I was reading a related thread on battery testers and wanted to switch the discussion to battery monitoring.

We have a house bank (8-6 volt series) and 2 starter banks (2-12 volt parallel) on our Cheoy Lee 46 Trawler. I recently changed all the batteries and want to install a monitoring system that will allow me to know the % of discharge, reserve and to monitor actual amp draw.

I would appreciate any advice or recommendations as anything having to do with electricity is like black magic to me.

Try doing a search on this forum, there are many threads in which this is discussed. You may not get a complete set of answers here since it has been a repeated subject. Do you have an inverter? How are you charging these batteries?

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George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"

I agree with John61ct. I would use the Balmar Smart Gauge. I donít have one but will be installing one at some point. I have an amp counter, and it works fine, but doesnít give me as accurate SOC% for my house bank as the Smart Gauge would.

The problem of course is evaluating its ongoing accuracy. Trailing amps while charging is always the best way to benchmark 100% SoC, and for lead, 10.5V is zero. Just the points in between are rough, always a guesstimate as usage patterns and SoH (%residual AH capacity) change over time.

Would be great if one could rent a SmartGauge by the month to help calibrate the SoH, Charge Efficiency and Peukert adjustments periodically required by coulomb-counting BMs.

After reviewing what was available in 2015, I went with the Victron SOC guage. While it offers a number of features, I primarily use the amps in / out display, and percentage of full charge. The gauge appears to be extremely accurate and has a self zeroing feature. After there is essentially no flow of amps in at full charge for a number of minutes, it resets the gauge valve to 100%. I would guess I have in excess of 300 cruising days since 2016 where the house bank was discharged between 5 and 25% and then recharged the next day. The Victron gauge has tracked it flawlessly. If it quit tomorrow, I'd buy another one.

Ted

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It is very common for charge sources to drop to Float (stop charging) prematurely.

Are you referring to a standard engine alternator? Or are you implying that multi stage externally regulated engine alternators and multi stage shore power battery chargers do that?

If the latter, could you link a reference showing that it's "very common ".

Ted

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Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush....."Slow Hand" by The Pointer Sisters

The simplest way to monitor Start batts is to have a volt meter that goes on with the key.

I think the simplest way to monitor all batteries on your boat is to install a Low cost SOC in each battery circuit. (On Amazon for about $9 each.) Simply walking through your boat will tell you the SOC at a glance. (12.7v is fully charged.)

Most of the coulomb counting monitors work pretty well for a few cycles and are in my mind preferable to voltage only monitors. That being said they all drift. Consult the manual from the manufacturer of your battery bank for an indication of fully charged. Usually .005C in amps. Once you hit that with your charger you should be fully charged. Iíve run three of he mentioned meters in this thread and my current preference is the victron but the new BMI 760. The Bluetooth interface actually allows you check and set almost everything with your iPhone from most anywhere onboard the boat. I usually do a capacity test every fall just to keep everyone honest. This year I found a liar.

I think the simplest way to monitor all batteries on your boat is to install a Low cost SOC in each battery circuit. (On Amazon for about $9 each.) Simply walking through your boat will tell you the SOC at a glance. (12.7v is fully charged.)

House, Engines & Genny

And don't you just love those Label Makers! Our daughter and son-in-law gave me one when we bought our boat - EVERYTHING in our boat will be labeled